In the disclosure of the present invention reference is mostly made to the treatment of diabetes by delivery of insulin-containing drugs, however, this is only an exemplary use of the present invention.
Drug injection devices (typically for subcutaneous delivery) have greatly improved the lives of patients who must self-administer drugs and biological agents. Drug injection devices may take many forms, including simple disposable devices that are little more than an ampoule with an injection means or they may be highly sophisticated electronically controlled instruments with numerous functions. Regardless of their form, they have proven to be great aids in assisting patients to self-administer injectable drugs and biological agents. They also greatly assist care givers in administering injectable medicines to those incapable of performing self-injections.
In particular pen-style injection devices have proven to provide an accurate, convenient, and often discrete, way to administer drugs and biological agents, such as insulin. Modern devices have become more sophisticated and often include diverse and robust functions, such as memories for remembering time and amount of last dose, as well as, in the case of insulin devices, blood glucose monitors. While pen-style injection devices are typically cylindrically shaped with a needle protruding from the most distal portion of one end of the device, some devices have other shapes with the needle no longer protruding from the most distal part of an end of the device, e.g. Innovo® and InnoLet® from Novo Nordisk A/S, Bagsvaerd, Denmark.
Typically, injection devices use a pre-filled cartridge containing the medication of interest, e.g. 1.5 or 3.0 ml of insulin or growth hormone. The cartridge is typically in the form of a generally cylindrical transparent ampoule with a needle pierceable septum at one end and an opposed piston designed to be moved by the dosing mechanism of the injection device. The injection devices generally are of two types: “Durable” devices and “disposable” devices. A durable device is designed to allow a user to replace one cartridge with another cartridge, typically a new cartridge in place of an empty cartridge. In contrast, a disposable device is provided with an integrated cartridge which cannot be replaced by the user; when the cartridge is empty the entire device is discarded. Most injection devices are provided with a releasable pen cap covering the cartridge and the needle mount portion (see below), this allowing the user to inspect the content of the cartridge by removing the cap.
Often injection devices are provided as a system or family of devices containing different types of drugs, e.g. as known from WO 2004/069314. This application discloses a system of substantially identical injection devices, each individual injection device comprising a housing accommodating an ampoule containing drug sufficient for a number of injections and a dose setting mechanism by which a predetermined dose size can be set, and wherein each of the plurality of injection devices has a different predetermined dose size. The difference in the predetermined dose sizes can in one embodiment be based on the drug in the devices having different strength.
People suffering from diabetes are often treated with multiple daily injections in a regimen comprising one or two daily injections of long acting insulin to cover the basal requirement supplemented by bolus injections of short or rapid acting insulin to cover requirements related to meals.
A user will therefore often require two different injection devices, one containing the long acting insulin and another containing the short or rapid acting insulin. Often these injection devices have different colour indications to inform the user of the kind of insulin contained in the injection device. For example, the FlexPen® system offered by Novo Nordisk comprises pens for long and short acting insulins as well as for mixed insulin, the bodies and caps being identical with colour markings on the main body to differentiate the two types of insulin. In the SoloStar® system offered by Sanofi-Aventis the pens for long and short acting insulins have differently coloured bodies as well as caps. In addition these injection devices can be provided with tactile means such as a mechanical coding informing the user of the kind of insulin contained in the injection device. DE U 201 10 689 discloses a pen-shaped injection device having a cap with a clip for holding the injection device e.g. in a pocket of a shirt. The injection device is contained in a cut-out in a box. The physical shape of the injection device is according to this reference designed such that the right injection device fits into the right box. This is according to the prior art done by having devices with different of length of the clip and boxes with a similar shaped cut-out. DE 201 10 690 discloses an injection device comprising a driver portion, a cartridge and a cartridge holder. The cartridge holder can be provided with a coded ring-shaped protecting member which allows only a specifically configured cartridge to be mounted in the cartridge holder.
Another technique for drug delivery is to use pulmonary delivery of an aerosolized pharmaceutical formulation so that the active drug within the dispersion can reach the more or less distal regions of the lung. This way of administration has been used extensively for e.g. local administration of drugs for treatment of respiratory deceases, e.g. asthma, but has also been proposed for the treatment of diabetes with insulin. A variety of aerosolization systems have been proposed to disperse pharmaceutical formulations. For example, U.S. Pat. No. 5,785,049 and U.S. Pat. No. 5,740,794, the disclosures of which are herein incorporated by reference, describe exemplary powder dispersion devices which utilize a compressed gas to aerosolize a powder. Other types of aerosolization systems include so-called MDI's (which typically have a drug that is stored in a propellant), nebulizers (which aerosolize liquids using compressed gas, usually air), and the like. Another technique is the use of inspired gases to disperse the pharmaceutical formulation. In this way, the patient is able to provide the energy needed to aerosolize the formulation by the patient's own inhalation. Corresponding to the administration of two or more drugs using injection devices, it may also be necessary to use two or more inhalation devices.
Although the prior art discloses a number of solutions of how to differentiate similar or otherwise identical drug delivery devices containing different kinds of drugs, there is still a need for drug delivery devices which in a simple and effective manner provides a strong identification of the kind of drug contained in a specific device, this reducing the risk of a user inadvertently taking the incorrect kind of drug.
Having regard to the above, it is an object of the present invention to provide a system of drug delivery devices which in a simple and cost-effective manner reduces the likelihood of a user taking the wrong kind of drug.